1. Field
The present disclosure generally relates to composite structures and, in particular, to the fabrication of composite structures. Still more particularly, the present disclosure relates to a method and apparatus for producing composite fillers used to fill gaps in composite structures.
2. Background
Aircraft are being designed and manufactured with greater and greater percentages of composite materials. Composite materials are used in aircraft to decrease the weight of the aircraft. This decreased weight improves performance features such as payload capacities and fuel efficiencies. Further, composite materials provide longer service life for various components in an aircraft.
Composite materials are tough, lightweight materials created by combining two or more functional components. For example, a composite material may include reinforcing fibers bound in a polymer resin matrix. The fibers may be unidirectional or may take the form of a woven cloth or fabric. In thermoset composites, fibers and resins are arranged and cured to form a composite material.
When composite structural members are joined together, gaps or voids may be present along bond lines between the members which may need to be filled in order to increase the strength of the bond. For example, in the aircraft industry, composite fuselage stiffeners such as stringers may include a composite filler at the radius bond line between the stringer and a fuselage skin. The composite filler is applied in the form of triangular cross-section strips, sometimes referred to as noodles or fillers, which fill the voids at the bond line. The composite filler may be formed from composite materials such as adhesive or prepreg tape.
These fillers may be prone to cracking. Cracking undesirably reduces the performance of the resulting composite structure. Cracking may be influenced by the material properties of at least one of the composite filler or the composite structural members.
Therefore, it would be desirable to have a method and apparatus that take into account at least some of the issues discussed above, as well as other possible issues. Specifically, one issue is to find a method and apparatus for preventing cracking in composite fillers.